Preface xv
Acknowledgments xix
Introduction xxi
About the Companion Website xxxi
Part I Linear Viscoelasticity and Experimental Methods 1
1 Phenomenological Description of Linear Viscoelasticity 3
1.1 Basic Modes of Deformation 3
1.2 Linear Responses 5
1.3 Classical Rubber Elasticity Theory 17
2 Molecular Characterization in Linear Viscoelastic Regime 23
2.1 Dilute Limit 23
2.2 Entangled State 30
2.3 Molecular-Level Descriptions of Entanglement Dynamics 39
2.4 Temperature Dependence 47
3 Experimental Methods 55
3.1 Shear Rheometry 55
3.2 Extensional Rheometry 63
3.3 In Situ Rheostructural Methods 66
3.4 Advanced Rheometric Methods 69
3.5 Conclusion 70
4 Characterization of Deformation Field Using Different Methods 75
4.1 Basic Features in Simple Shear 75
4.2 Yield Stress in Bingham-Type (Yield-Stress) Fluids 77
4.3 Cases of Homogeneous Shear 79
4.4 Particle-Tracking Velocimetry (PTV) 79
4.5 Single-Molecule Imaging Velocimetry 83
4.6 Other Visualization Methods 83
5 Improved and Other Rheometric Apparatuses 87
5.1 Linearly Displaced Cocylinder Sliding for Simple Shear 88
5.2 Cone-Partitioned Plate (CPP) for Rotational Shear 88
5.3 Other Forms of Large Deformation 91
5.4 Conclusion 96
Part II Yielding - Primary Nonlinear Responses to Ongoing Deformation 99
6 Wall Slip - Interfacial Chain Disentanglement 103
6.1 Basic Notions of Wall Slip in Steady Shear 104
6.2 Stick-Slip Transition in Controlled-Stress Mode 108
6.3 Wall Slip during Startup Shear - Interfacial Yielding 116
6.4 Relationship between Slip and Bulk Shear Deformation 120
6.5 Molecular Evidence of Disentanglement during Wall Slip 131
6.6 Uncertainties in Boundary Condition 134
6.7 Conclusion 134
7 Yielding during Startup Deformation: From Elastic Deformation to Flow 139
7.1 Yielding at Wi<1 and Steady Shear Thinning at >1 140
7.2 Stress Overshoot in Fast Startup Shear 143
7.3 Nature of Steady Shear 154
7.4 From Terminal Flow to Fast Flow under Creep: Entanglement-Disentanglement Transition 159
7.5 Yielding in Startup Uniaxial Extension 163
7.6 Conclusion 175
8 Strain Hardening in Extension 181
8.1 Conceptual Pictures 181
8.2 Origin of "Strain Hardening" 184
8.3 True Strain Hardening in Uniaxial Extension: Non-Gaussian Stretching from Finite Extensibility 188
8.4 Different Responses of Entanglement to Startup Extension and Shear 190
8.5 Conclusion 190
9 Shear Banding in Startup and Oscillatory Shear: Particle-Tracking Velocimetry 195
9.1 Shear Banding After Overshoot in Startup Shear 197
9.2 Overcoming Wall Slip during Startup Shear 209
9.3 Nonlinearity and Shear Banding in Large-Amplitude Oscillatory Shear 214
10 Strain Localization in Extrusion, Squeezing Planar Extension: PTV Observations 221
10.1 Capillary Rheometry in Rate-Controlled Mode 221
10.2 Instabilities at Die Entry 226
10.3 Squeezing Deformation 230
10.4 Planar Extension 233
11 Strain Localization and Failure during Startup Uniaxial Extension 235
11.1 Tensile-Like Failure (Decohesion) at Low Rates 237
11.2 Shear Yielding and Necking-Like Strain Localization at High Rates 239
11.3 Rupture-Like Breakup: Where Are Yielding and Disentanglement? 245
11.4 Strain Localization Versus Steady Flow: Sentmanat Extensional Rheometry Versus Filament-Stretching Rheometry 247
11.5 Role of Long-Chain Branching 250
Part III Decohesion and Elastic Yielding After Large Deformation 255
12 Nonquiescent Stress Relaxation and Elastic Yielding in Stepwise Shear 257
12.1 Strain Softening After Large Step Strain 258
12.2 Particle Tracking Velocimetry Revelation of Localized Elastic Yielding 265
12.3 Quiescent and Uniform Elastic Yielding 279
12.4 Arrested Wall Slip: Elastic Yielding at Interfaces 283
12.5 Conclusion 286
13 Elastic Breakup in Stepwise Uniaxial Extension 291
13.1 Rupture-Like Failure during Relaxation at Small Magnitude or Low Extension Rate (WiR <1) 292
13.2 Shear-Yielding-Induced Failure upon Fast Large Step Extension (WiR >1) 293
13.3 Nature of Elastic Breakup Probed by Infrared Thermal-Imaging Measurements 297
13.4 Primitive Phenomenological Explanations 298
13.5 Step Squeeze and Planar Extension 299
14 Finite Cohesion and Role of Chain Architecture 301
14.1 Cohesive Strength of an Entanglement Network 302
14.2 Enhancing the Cohesion Barrier: Long-Chain Branching Hinders Structural Breakup 306
Part IV Emerging Conceptual Framework and Beyond 311
15 Homogeneous Entanglement 313
15.1 What Is Chain Entanglement? 313
15.2 When, How, and Why Disentanglement Occurs? 315
15.3 Criterion for Homogeneous Shear 316
15.4 Constitutive Nonmonotonicity 318
15.5 Metastable Nature of Shear Banding 319
16 Molecular Networks as the Conceptual Foundation 325
16.1 Introduction: The Tube Model and its Predictions 326
16.2 Essential Ingredients for a New Molecular Model 333
16.3 Overcoming Finite Cohesion after Step Deformation: Quiescent or Not 339
16.4 Forced Microscopic Yielding during Startup Deformation: Stress Overshoot 341
16.5 Interfacial Yielding via Disentanglement 346
16.6 Effect of Long-Chain Branching 347
16.7 Decohesion in Startup Creep: Entanglement-Disentanglement Transition 349
16.8 Emerging Microscopic Theory of Sussman and Schweizer 350
16.9 Further Tests to Reveal the Nature of Responses to Large Deformation 351
16.10 Conclusion 354
17 "Anomalous" Phenomena 361
17.1 Essence of Rheometric Measurements: Isothermal Condition 361
17.2 Internal Energy Buildup with and without Non-Gaussian Extension 366
17.3 Breakdown of Time-Temperature Superposition (TTS) during Transient Response 368
17.4 Strain Hardening in Simple Shear of Some Polymer Solutions 372
17.5 Lack of Universal Nonlinear Responses: Solutions versus Melts 374
17.6 Emergence of Transient Glassy Responses 378
18 Difficulties with Orthodox Paradigms 385
18.1 Tube Model Does Not Predict Key Experimental Features 385
18.2 Confusion About Local and Global Deformations 391
18.3 Molecular Network Paradigm 392
19 Strain Localization and Fluid Mechanics of Entangled Polymers 397
19.1 Relationship between Wall Slip and Banding: A Rheological-State Diagram 398
19.2 Modeling of Entangled Polymeric Liquids by Continuum Fluid Mechanics 399
19.3 Challenges in Polymer Processing 400
20 Conclusion 409
20.1 Theoretical Challenges 410
20.2 Experimental Difficulties 413
References 415
Symbols and Acronyms 417
Subject Index 421
